I currently have two female mice in a ten gallon tank. I have heard that groups of three are better and I am wondering if I should get a third. I am a first time mouse owner but I have had a lot of rats in the past including ones I needed to tame. I know mice and rats arent the same but I feel like the experience may help with mice.

Is a ten gallon enough for three or will I have to look into getting an upgrade?I've had my mice for two days, if I get the third from the same place will they still remember or will I have to do introductions? If so how is that done? Is it alike from rat introductions?